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Comparison of Goldmann applanation tonometer, Tono-Pen and noncontact tonometer in children
Usha Kaul Raina1, Neha Rathie1, Anika Gupta1
1Department of Ophthalmology, Guru Nanak Eye Centre, Maulana Azad Medical College, New Delhi, India.
Insights
Intraocular pressure (IOP) measurements in children differ significantly between noncontact tonometer (NCT), Tono-Pen, and Goldmann applanation tonometer (GAT). Central corneal thickness (CCT) also impacts IOP readings, necessitating further research for accurate pediatric IOP assessment.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Glaucoma Research
Background:
- Intraocular pressure (IOP) measurement is crucial for diagnosing and managing pediatric glaucoma.
- Variability in IOP readings among different tonometers can affect clinical decisions.
- The influence of central corneal thickness (CCT) on IOP measurements in children requires further investigation.
Purpose of the Study:
- To compare the agreement of Goldmann applanation tonometer (GAT) with Tono-Pen and noncontact tonometer (NCT) for IOP measurement in children.
- To assess the correlation between central corneal thickness (CCT) and IOP readings obtained from these tonometers in a pediatric cohort.
Main Methods:
- IOP was measured in 200 pediatric eyes (ages 8-18) using NCT, Tono-Pen, and GAT.
- Inter-tonometer agreement was analyzed using the Bland-Altmann method.
- Linear regression analyzed the relationship between CCT and IOP values, as well as inter-tonometer differences.
Main Results:
- Mean IOP values were 14.38 mmHg (NCT), 15.63 mmHg (Tono-Pen), and 12.44 mmHg (GAT).
- Tono-Pen and NCT yielded statistically higher IOP readings than GAT, irrespective of CCT.
- Significant correlations were observed between CCT and IOP values across all three tonometers.
Conclusions:
- Pediatric IOP measurements show significant inter-instrument variability.
- Corneal thickness influences IOP readings, impacting the reliability of different tonometers.
- Further studies are essential to establish the most appropriate tonometer and normative IOP ranges for children.
Background:
To evaluate the agreement of Goldmann applanation tonometer (GAT) with Tono-Pen and noncontact tonometer (NCT) for measurement of intraocular pressure (IOP) in pediatric age group and to evaluate the correlation between central corneal thickness (CCT) and IOP measured with the tonometers used.
Materials And Methods:
IOP was measured in 200 eyes in a group of Indian children, aged between 8 and 18 years using three different tonometers: NCT, the Tono-Pen and GAT. All IOP readings were made in the office settings by the same examiner. Readings obtained were compared between the instruments and with the CCT for each tonometer. Tonometer inter-method agreement was assessed by the Bland-Altmann method. The relations of CCT with absolute IOP values and inter-tonometer differences were analyzed by linear regression.
Results:
The mean age was 13.37 3.51 years. The mean IOP values recorded with NCT; Tono-Pen and GAT were 14.38, 15.63, and 12.44 mmHg, respectively. Both Tono-Pen and NCT recorded statistically higher IOP values than the GAT (P = 0.00) regardless of the CCT. The percentage increase of IOP measured over GAT was 15.66% for NCT and 25.70% for Tono-Pen which was also statistically significant. A correlation was found between CCT and IOP values obtained with all the three tonometers.
Conclusion:
IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which instrument is most appropriate and to derive a normative IOP scale for the growing eye.
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